Frequently a level gauge application requires the wetted parts to be of Hastelloy, Zirconium, Titanium or other exotic materials because of the highly corrosive nature of the material being measured. These materials work in such cases, but they are expensive and require special welding techniques.

Typically a Hastelloy gauge will run three times the price of a stainless steel one. ISE-Magtech can make gauges from solid Kynar. This material is similar to Teflon but is less porous.

A Kynar gauge is fabricated using all Kynar flanges, floats, etc. It is also limited in temperature to about 280 degrees F. In many applications where temperature and pressure are not extreme, the Kynar gauge is an ideal substitute for the exotic metals. It is only about 25 - 30% more than stainless but about half the price of a Hastelloy gauge.

Any time you wonder about the compatibility of measured liquid with the gauge material, contact ISE-Magtech. They have some very extensive sets of corrosion tables that cover almost all the chemicals you may come across.

Don't forget, for ambient tanks, PVC / CPVC is a good material and is much less expensive than stainless steel.